This invention relates to an X-Y table device for use with a sewing machine which performs the embroidering of a variety of patterns on cloths.
An X-Y table device of this type is used to embroider a variety of patterns on cloths with a sewing machine as shown in FIGS. 6 and 7. In the figures, reference numeral 1 designates a sewing machine head in which a sewing mechanism including a sewing needle and its drive system is built; 2, a bed supporting the sewing machine head and incorporating an X-Y table device, the head and the bed being arranged on a table stand 3; and 9, a cloth retainer arranged below the sewing needle of the head 1. The cloth retainer 9 is coupled to a retaining arm 8 at one end. At the other end of the retaining arm 8 a supporting piece 8a extended therefrom is secured to the movable stand 10a of the X-Y table 10 provided in the bed 2 with screws. A shaft support 12 is fixedly secured to the end face of the support piece 8a with screws. Further in FIG. 7, reference numeral 13 designates a bearing; 14, a slide shaft; and 15, a drive shaft. In response to control signals from an electronic control board 7 (FIG. 6), electric motors 11a and 11b such as stepping motors or servo motors drive the X-Y table 10 two-dimensionally.
The operation of the sewing machine thus constructed will be described. First, a start switch 6 is turned on and then a start switch 5 for starting a sewing operation is turned on. As a result, in synchronization with the operation of the sewing machine head 1, the retaining arm 8, the supporting piece 8a, the shaft support 12, the slide shaft 14, the bearing 13 and the drive shaft 15 are moved over the bed by the X-Y table 10 according to a desired pattern stored in a memory medium 4 which has stored patterns programmed in advance, so that the desired pattern is embroidered on the cloth held by the cloth retainer 9 with the aid of the retaining arm 8.
In the sewing machine with the conventional X-Y table device, the cloth retaining mechanism is provided on the side of the retaining arm 8. Therefore, in the case where, in a sewing operation, its accuracy and speed are essential factors, it is necessary to reduce the weight and deflection of the members between the cloth retainer 9 and the motors 11a and 11b as much as possible. In a large area sewing machine which is so designed that the cloth retainer is movable over a wide range, its components are large in weight accordingly, and the movement of the cloth retainer is greatly resisted. Accordingly, with the large area sewing machine, in a continuous sewing operation and particularly in an intermittent sewing operation, the retaining arm 8, the slide shaft 14, the bearing 12, the X-Y table 10, and the drive shaft 15 may be swung horizontally, or they may be deflected, so that it becomes difficult to achieve the sewing operation at high speed with high accuracy.